EDIT

package eu.etaxonomy.cdm.vaadin.ui;

import java.util.logging.Logger;

import org.springframework.security.core.Authentication;

import com.vaadin.navigator.Navigator;

import com.vaadin.server.VaadinRequest;

import com.vaadin.server.VaadinSession;

import com.vaadin.ui.UI;

import eu.etaxonomy.cdm.vaadin.presenter.AuthenticationPresenter;

import eu.etaxonomy.cdm.vaadin.view.AuthenticationView;

public abstract class AbstractAuthenticatedUI extends UI {

	Navigator navigator;

	private static final String AUTHENTICATION_VIEW = "abstractAuthenticatedUI";

	private final static Logger logger =

			Logger.getLogger(AbstractAuthenticatedUI.class.getName());

	@Override

	protected void init(VaadinRequest request) {		

        // Create a navigator to control the views

        navigator = new Navigator(this, this);

        AuthenticationView av = new AuthenticationView();

        navigator.addView(AUTHENTICATION_VIEW, av);

        new AuthenticationPresenter(av);

        // Create and register the views

        Authentication authentication = (Authentication) VaadinSession.getCurrent().getAttribute("authentication");			

        doInit();

        if(authentication != null && authentication.isAuthenticated()) {

        	UI.getCurrent().getNavigator().navigateTo(getFirstViewName());

        } else {

        	UI.getCurrent().getNavigator().navigateTo(AUTHENTICATION_VIEW);

        }

	}

	protected abstract void doInit();

	public abstract String getFirstViewName();

}